Adjustable multi-turn magnetic coupling device

ABSTRACT

According to some embodiments, an integrated circuit device is disclosed. The integrated circuit device include at least one inductor having at least one turn, a magnetic coupling ring positioned adjacent to the at least one inductor, the magnetic coupling ring comprising at least two magnetic coupling turns, the at least two magnetic coupling turns are disposed adjacent to the at least one turn to enable magnetic coupling between the at least two magnetic coupling turns and the at least one turn. The integrated circuit device also includes a power electrode and a ground electrode, wherein the power electrode and the ground electrode are coupled to the at least one inductor and the magnetic coupling ring to provide a first current in the at least one inductor having a direction opposite to a second current in the magnetic coupling ring to cancel at least a portion of a magnetic field generated by the at least one inductor.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.15/151,098, filed 10 May 2016, which is a utility of and claims priorityto provisional application entitled “Adjustable Multi-Turn MagneticCoupling Technique For LC-Based DCO”, Application No. 62/269,699, filedon 18 Dec. 2015, the entirety of which are incorporated herein byreference.

BACKGROUND

All-digital phase-lock-loops (ADPLLs) are widely used in advanced CMOStechnology. ADPLLs typically include high resolution time-to-digitalconverters (TDC) and LC-based digitally controlled oscillators (LC-DCO).Such configuration reduces area consumption and power dissipation in theADPLL. The ADPLL also typically includes a digital loop filter, areference clock accumulator, a variable clock accumulator and a feedbackdivider.

Compared to analog phase lock loops, an ADPLL with an LC-DCO exhibitslower phase noise with lower power consumption and lower frequencypushing (i.e., smaller output frequency variations due to supply voltagevariation and/or noise). In addition, the LC-DCO is generally immunefrom process and temperature variations. The ADPLL with an LC-DCO,however, has a relatively smaller tuning range and occupies a relativelylarge space on the chip when compared to analog PLLs, for example.

Magnetic coupling techniques can be used for increasing the tuning rangewithout extra area consumption by an LC-DCO by decreasing the inductanceof an inductor or transformer-based LC tank of the LC-DCO.Implementations with a single-turn and fixed switches, however, providea limited tuning range extension. Additionally, such magnetic couplingtechniques decrease the total quality factor of the LC tank of the LCDCO due to a switch resistor coupling effect.

BRIEF DESCRIPTION OF THE DRAWINGS

Aspects of the present disclosure are best understood from the followingdetailed description when read with the accompanying figures. It isnoted that various features are not necessarily drawn to scale. In fact,the dimensions of the various features may be arbitrarily increased orreduced for clarity of discussion.

FIG. 1A is a three dimensional view of a stacked compact transformerlayout with two inductors L₁ and L₂ in accordance with some embodiments.

FIG. 1B is a layout diagram illustrating the OFF state of a multi-turnmagnetic coupling transformer in accordance with some embodiments.

FIG. 1C is a layout diagram illustrating the ON state of a multi-turnmagnetic coupling transformer in accordance with some embodiments.

FIG. 2A is a layout diagram illustrating a multi-turn magnetic couplingtransformer with the number of turns N=2 in accordance with someembodiments.

FIG. 2B is a layout diagram illustrating a multi-turn magnetic couplingtransformer with the number of turns N=3 in accordance with someembodiments.

FIG. 2C is a bar graph chart illustrating a comparison of performanceenhancement of N=1, 2 and 3 in accordance with some embodiments.

FIG. 3A is a layout diagram illustrating an outside coupling inaccordance with some embodiments.

FIG. 3B is a layout diagram illustrating an inside coupling inaccordance with some embodiments.

FIG. 3C is a layout diagram illustrating a surface inside-outsidecoupling in accordance with some embodiments.

FIG. 4A is a layout diagram illustrating a top coupling in accordancewith some embodiments.

FIG. 4B is a layout diagram illustrating a bottom coupling in accordancewith some embodiments.

FIG. 4C is a layout diagram illustrating a vertical top-bottom couplingin accordance with some embodiments.

FIGS. 5A and 5B provide graphs illustrating the magnetic couplingswitching-on effect on the quality factor of a single switch.

FIGS. 5C and 5D provide graphs illustrating the magnetic couplingswitching-on effect on the quality factor of two switches.

FIG. 6A is a layout diagram illustrating an adjustable multi-turnmagnetic coupling transformer with two switches in accordance with someembodiments.

FIG. 6B is a graph illustrating a comparison of the inductance andswitch resistance of an adjustable multi-turn magnetic couplingtransformer with two switches in accordance with some embodiments.

FIG. 7 is a layout diagram illustrating an adjustable multi-turnmagnetic coupling transformer with NMOS switches in accordance with someembodiments.

FIG. 8A is a schematic diagram illustrating the circuit implementationof an adjustable multi-turn magnetic coupling transformer in accordancewith some embodiments.

FIG. 8B is a schematic plot illustrating the signal waveforms on VD+/−,VG+/−, BUF+/− and FOUT respectively in FIG. 8A in accordance with someembodiments.

FIG. 9 is a layout diagram illustrating the point-symmetricpseudo-differential layout corresponding to the circuit implementationof an adjustable multi-turn magnetic coupling transformer in FIG. 8A inaccordance with some embodiments.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

The following disclosure provides many different embodiments, orexamples, for implementing different features of the subject matter.Specific examples of components and arrangements are described below tosimplify the present disclosure. These are, of course, merely examplesand are not intended to be limiting. For example, the formation of afirst feature over or on a second feature in the description thatfollows may include embodiments in which the first and second featuresare formed in direct contact, and may also include embodiments in whichadditional features may be formed between the first and second features,such that the first and second features may not be in direct contact. Inaddition, the present disclosure may repeat reference numerals and/orletters in the various examples. This repetition is for the purpose ofsimplicity and clarity and does not in itself dictate a relationshipbetween the various embodiments and/or configurations discussed.

Further, spatially relative terms, such as “beneath,” “below,” “lower,”“above,” “upper” and the like, may be used herein for ease ofdescription to describe one element or feature's relationship to anotherelement(s) or feature(s) as illustrated in the figures. The spatiallyrelative terms are intended to encompass different orientations of thedevice in use or operation in addition to the orientation depicted inthe figures. The apparatus may be otherwise oriented (rotated 90 degreesor at other orientations) and the spatially relative descriptors usedherein may likewise be interpreted accordingly. Additionally, it will beunderstood that when an element is referred to as being “connected to”or “coupled to” another element, it may be directly connected to orcoupled to the other element, or one or more intervening elements may bepresent.

FIG. 1A is a three dimensional layout view of a stacked compacttransformer 150 that includes two inductors, a first inductor (L₁) 101and a second inductor (L₂) 102, in accordance with some embodiments.According to some embodiments, both the first and second inductors 101and 102 are deployed in two tiers: tier A and tier B. In someembodiments, tier A and tier B are parallel to each other. According tosome embodiments, the tier A portion of the first inductor 101A runscounter clockwise, while the tier B portion of the first inductor 101Balso runs counter clockwise. According to some embodiments, the innerend of coil 101A is 101VA, and the inner end of 101B is 101VB. The innerends 101VA and 101VB are aligned, and a plurality of vias, i.e. 101V,are implemented to electrically connect the inner end 101VA of coil 101Aand the inner end 101VB of coil 101B across the tiers A and B.Similarly, a plurality of vias 102V are implemented to electricallyconnect the inner end 102VA of coil 102A and the inner end 102VB of coil102B.

According to some embodiments, when the coils 101A and 101B areconnected by vias 101V to form the inductor 101, the electrical currentflows in to the inductor 101 from the L1A end and then counter clockwiseto the inner end 101VA. After crossing from tier A to tier B through thevias 101V, the current flows counter clockwise from the inner end 101VBto the L1B end. Similarly, electrical current flows in to the inductor102 from the L2A end and flows out from the L2B end.

FIG. 1B is a layout diagram illustrating a transformer 100 having afirst inductor 101 (L₁), a second inductor 102 (L₂) and a magneticcoupling ring 103 disposed outside and adjacent to the first and secondinductors 101 and 102, respectively. According to some embodiments, thefirst inductor L₁ 101 and the second inductor L₂ 102 have the threedimensional layout illustrated in FIG. 1A. FIG. 1B illustrates a topview of the first inductor L₁ 101 and the second inductor L₂ 102 withthe magnetic coupling ring 103 disposed outside. In the present topview, the coils 101A and 102A in the tier A overlap on the top of thecoils 101B and 102B in the tier B. As explained in FIG. 1A above,electrical current flows in to the L2A end of the inductor 102 and flowscounter clockwise. When the current reaches the inner end 102VA, thecurrent crosses from the tier A to the tier B through the vias 102V. Inthis top view, the flow of electrical current in tier B is not visiblebecause it is overlapped by tier A. The electrical current exits theinductor 102 at the L2B end. Similarly, the electrical current flows into the inductor 101 from the L1A end and flows out from the L1B end.

The transformer 100 can be used in an LC-DCO, for example, in accordancewith some embodiments. One or more turns (N≥1) of magnetic couplingprovided by the magnetic coupling ring 103 can be implemented to enhancethe magnetic field cancellation effect, thus to enhance the operationfrequency of the DCO. In the embodiment illustrated in FIGS. 1B and 1C,the magnetic coupling ring 103 has only a single turn 103 (N=1). Anincrease in turns can produce a larger magnetic field for cancelling themagnetic field produced by the first and second inductors 101 and 102,which results in a smaller total inductance of the transformer 100, asdiscussed in further detail below. According to some embodiments, avariable switch 104 (represented as a variable resistor in the figures)controls the ON and OFF states of the magnetic coupling ring 103.According to some embodiments, the variable switch 104 includes morethan one switch. A fixed switch can only be switched between two states:ON and OFF. As a comparison, a variable switch can have one or morestates between ON and OFF so that the switch can be in a partially ONstate. The variable switch will be discussed with FIGS. 5A-5D, 6A-6B,and 7 below. When the variable switch 104 is switched to the OFF state,no current flows in the magnetic coupling ring 103. When the variableswitch 104 is switched ON, current flows in the magnetic coupling ring103.

In FIG. 1B, the second inductor 102 is turned on such that AC current isrunning through it. However, the magnetic coupling ring 103 is in theOFF state such that no electrical current flows in the magnetic couplingturn 101. As a result, no additional magnetic field is generated by themagnetic coupling turn 101. As shown in FIG. 1B, the second inductor 102is disposed inside the magnetic coupling ring 103 and electrical currentflows counter clock-wise in the second L₂ inductor 102 to generate amagnetic field. The first L₁ inductor 101 is disposed inside the secondL₂ inductor 102. As discussed in further detail below, the magneticcoupling turn(s) 103 can be switched ON and OFF by variable switch 104,for example, to decrease the total magnetic field of the transformer 100and increase the tuning range of a LC-DCO. According to someembodiments, the L₁ inductor 101 and the L₂ inductor 102 couple to forma 4-port transformer according to Faraday's law.

The four ports are designated as L1A, L2A, L1B and L1B, where L1A is theinput port of the first L₁ inductor 101, L1B is the output port of thefirst L₁ inductor 101, L2A is the input port of the second L₂ inductor102, and L2B is the output port of the second L₂ inductor 102. Theinductors 101 and 102 are illustrated in different shades in FIGS. 1B,1C, and all subsequent figures. The direction of the magnetic fieldgenerated by current flow in the second L₂ inductor 102 is illustratedas ⊙ in the center of the turns, which means the direction of themagnetic field points downward into the turn (i.e., perpendicularly intothe plane of the page). When current flows in the inductors 101 and 102,they magnetically couple to form a transformer. According to someembodiments, the dimensions (e.g., length, width, thickness) of theinductors 101 and 102 and the magnetic coupling ring 103 are in themicron scale as shown in FIG. 9, for example.

When the magnetic coupling ring 103 is switched OFF, the magneticcoupling ring 103 does not generate an additional magnetic field. Whenthe magnetic coupling ring 103 is switched ON, the magnetic couplingring 103 generates a magnetic field in a direction opposite to themagnetic field generated by the current in the inductors 101 and 102 todecrease the overall magnetic field of the transformer 100.

FIG. 1C is a layout diagram illustrating the ON state of the magneticcoupling ring 103, in accordance with some embodiments. In the ON state,the magnetic coupling ring 103 is switched to an ON state by anappropriate switching mechanism. When switched ON, the electricalcurrent flows clockwise inside the magnetic coupling ring 103, whichgenerates a magnetic field opposite to the magnetic field generated bythe electrical current in the L₂ turn or inductor 102. The direction ofthe magnetic field generated by the electrical current in the magneticcoupling ring 103 is illustrated as a cross with a circle in the centerof the turns, which is perpendicular out of the plane of the page.According to some embodiments, the switching mechanism for the magneticcoupling ring 103 can be a MOS transistor, or bipolar junctiontransistor, or a combination of MOS transistors and bipolar junctiontransistors.

According to some embodiments, the total magnetic fieldB_(TOTAL)=B_(TF)−B_(MC), where B_(TF) is the magnetic field generated bythe transformer formed by the first and second inductors 101 and 102,respectively, and B_(MC) is the magnetic field generated by the magneticcoupling ring 103. The magnetic coupling field B_(MC) is proportional tothe coupling coefficient K_(M), such that B_(MC) ∝I K_(M), where I isthe current through the magnetic coupling ring 103 and the magneticcoupling coefficient K_(M) is limited by the spacing of the metal designrules. When the spacing between the second inductor 102 and the magneticcoupling ring 103 decreases, K_(M) increases. From the relationshipB_(MC) ∝I K_(M), in order to maximize B_(MC), I should be maximized,which in turn suggests that the resistance of the switching mechanism beminimized. According to some embodiments, when MOS transistors areimplemented as switching mechanisms, then the MOS switch resistance Ronshould be minimized.

According to some embodiments, by switching ON the magnetic couplingring 103, the total magnetic field B_(TOTAL) is reduced, which resultsin a decrease in the mutual inductance (L) of the transformer(comprising inductors L₁ 101 and L₂ 102). According to the formula:f_(osc)=1/[2π·Sqrt(L·C)], when L decreases, f_(osc) increases. Morespecifically, when L decreases 33%, f_(osc) increases approximately 25%.When the magnetic coupling is not turned on, the tuning range of theLC-based digitally controlled oscillators (LC-DCO) is 10 GHz-17 GHz.When the magnetic coupling is turned on and L is reduced by 33%, thefrequency turning range is increased to 10 HGz˜20 GHz, an approximately25% increase.

FIG. 2A is a layout diagram illustrating a transformer 200 having afirst L₁ inductor 201, a second L₂ inductor 202 and a two-turn (N=2)magnetic coupling ring 203, in accordance with some embodiments. Theinductors 201 and 202 have similar three dimensional layout asillustrated in FIG. 1A. The magnetic coupling inductor 203 includes afirst magnetic coupling turn 203A and a second magnetic coupling turn203B disposed inside the first magnetic coupling turn 203A. The magneticcoupling turns 203A and 203B form the magnetic coupling ring 203 that iscontrolled by the variable switch 204. The first and second magneticcoupling turns 203A and 203B are connected so that the current flows inthe same direction in both turns. According to some embodiments, whenthe magnetic coupling ring 203 is switched to the ON state (i.e., whenthe variable switch 204 is turned ON), electrical current flows insidethe magnetic coupling turns 203A and 203B in a direction opposite thedirection of the electrical current inside the first and secondinductors 201 and 202, respectively. As a result, the magnetic fieldgenerated by the AC current in the magnetic coupling turns 203A and 203Bis in the opposite direction of the magnetic field generated by the ACcurrent in the first and second inductors 201 and 202. Thus, thealternating current (AC) flow in the magnetic coupling turns 203A and203B are approximately 180 degrees out of phase with respect to the ACcurrent flow in the first and second inductors 201 and 202. Thus,according to Lenzs law, the two magnetic field have a cancellationeffect upon each other and reduce the total magnetic field of thetransformer 200, which results in a reduction in total inductance (L) ofthe transformer 200. As discussed above with respect to FIGS. 1B and 1C,when the inductance is reduced, the frequency tuning range is extendedapproximately 25%.

FIG. 2B is a layout diagram illustrating a transformer 210 having afirst L₁ inductor 211, a second L₂ inductor 212 and a three-turn (N=3)magnetic coupling ring 213, in accordance with some embodiments. Theinductors 211 and 212 have similar three dimensional layout asillustrated in FIG. 1A. In addition to the two magnetic coupling turns213A and 213B, a third magnetic coupling turn 213C is disposed outsidethe magnetic coupling turns 213A and 213B. The magnetic coupling turns213A, 213B and 213C form the magnetic coupling ring 213 controlled bythe variable switch 214. The magnetic coupling turns 213A, 213B and 213Care all connected so that, when all three magnetic coupling turns areswitched to the ON (or partial ON) state, electrical AC current flowsinside the magnetic coupling turns 213A, 213B and 213C in the samedirection. As a result, magnetic field is generated by the magneticcoupling turns 213A, 213B and 213C. Thus, the alternating current (AC)flow in the magnetic coupling turns 213A, 213B and 213C areapproximately 180 degrees out of phase with respect to the AC currentflow in the first and second inductors 201 and 202. According to someembodiments, the direction of the magnetic field generated by themagnetic coupling turns 213A, 213B and 213C is opposite to the magneticfield generated by the inductors 211 and 212. Similar to the discussionit FIGS. 1B and 1C, the L₁ inductor 211 and L₂ inductor 212 of the areillustrated in different shades.

FIG. 2C is a bar graph chart illustrating a comparison of performanceenhancement when the magnetic coupling ring has one, two and three turns(N=1, 2 and 3), in accordance with some embodiments. The performance ismeasured by the extension of the frequency tuning range as a percentage.As illustrated in the figure, the performance enhancement reaches amaximum value of about 24% when the number of turns is N=2. When thenumber of turns increases to N=3, parasitic capacitance is induced andthe performance enhancement drops to around 21%. When the number ofturns further increases to N=4, further parasitic capacitance is inducedand the performance enhancement further decreases to around 15%, whichis close to the same level when N=1. According to some embodiments, N=2reaches the optimal enhancement of the performance for the embodimentsand configurations illustrated in FIGS. 1A-2B. According to alternativeembodiments, the magnetic coupling ring can be disposed adjacent to theinductors L₁ and/or L₂ in alternative configurations, and N can be anyinteger number larger than 1.

FIG. 3A is a layout diagram illustrating a transformer 300 having atransformer/inductor 302 and two outside magnetic coupling turns 301Aand 301B in accordance with some embodiments. The magnetic couplingturns 301A and 301B form a magnetic coupling ring 301. Thetransformer/inductor 302 can be an inductor or transformer but isillustrated as a single turn inductor for purposes of simplicity. Themagnetic coupling turns 301A and 301B are outside coupling turnsdisposed outside the inductor or transformer 302, which means that boththe magnetic coupling turns 301A and 301B have larger sizes than thetransformer 302. According to some embodiments, the turn 302 is atransformer which has two inductors (not illustrated in FIG. 3A) similarto the embodiments in FIGS. 1B and 1C. According to some embodiments,the transformer/inductor 302 is a transformer which has more than twoinductors. According to some embodiments, the magnetic coupling turns301A and 301B magnetically couple with the transformer/inductor 302 toform the transformer 300. According to some embodiments, the magneticcoupling turns 301A, 301B and transformer/inductor 302 are all in thesame plane or layer of an integrated circuit. The magnetic couplingturns 301A and 301B are electrically connected to allow electricalcurrent to flow through both of them in the same direction. According tosome embodiments, additional turns can be added to thetransformer/inductor 302. According to some embodiments, additionalturns can be added outside the transformer/inductor 302, andelectrically connected to magnetic turns 301A and 301B to form amagnetic coupling ring with more turns. In some embodiments, the spacebetween the transformer/inductor 302 and magnetic turns 301A, 301B isfilled with non-magnetic material.

FIG. 3B is a layout diagram illustrating a transformer 310 having atransformer/inductor 312 and two inside magnetic coupling turns 311A and311B, in accordance with some embodiments. The magnetic coupling turns311A and 311B form a magnetic coupling ring 311. Thetransformer/inductor 312 is an inductor, or a transformer, the magneticcoupling turns 311A and 311B are inside coupling turns disposed insidethe transformer/inductor 312, which means that both of the magneticcoupling turns 311A and 311B have smaller sizes than the transformer312. According to some embodiments, the magnetic coupling turns 311A and311B magnetically couple with the transformer/inductor 312 to form thetransformer 310. According to some embodiments, the magnetic couplingturns 311A, 311B and transformer/inductor 312 are all planar turnsformed on the same plane or layer in an integrated circuit. The magneticcoupling turns 311A and 311B are electrically connected to allowelectrical current to flow through both of them in the same direction.According to some embodiments, additional turns can be added to thetransformer/inductor 312. According to some embodiments, additionalturns can be added inside the transformer/inductor 312, and electricallyconnected to the magnetic coupling turns 311A and 311B to form amagnetic coupling ring with more turns. In some embodiments, the spacebetween the transformer/inductor 312 and the magnetic coupling turns311A and 311B is filled with non-magnetic material.

FIG. 3C is a layout diagram illustrating a transformer 320 having atransformer/inductor 322, an outside magnetic coupling turn 321A and aninside magnetic coupling turn 321B, in accordance with some embodiments.The magnetic coupling turns 321A and 321B form a magnetic coupling ring321. The magnetic coupling turn 321A is an outside coupling turndisposed outside the transformer/inductor 322, which means that themagnetic coupling turn 321A has a larger size than thetransformer/inductor 322. The magnetic coupling turn 321B is an insidecoupling turn disposed inside the inductor 322, which means that themagnetic coupling turn 321B has a smaller size than thetransformer/inductor 322. The magnetic coupling turns 321A and 321B areelectrically connected to allow electrical current to flow through bothof them in the same direction. According to some embodiments, themagnetic coupling turns 321A, 321B and transformer/inductor 322 are allin the same plane. According to some embodiments, additional turns canbe added to the transformer/inductor 322. According to some embodiments,additional turns can be added outside the transformer/inductor 322.According to some embodiments, additional turns can be added inside thetransformer/inductor 322, and electrically connected to the magneticcoupling turns 321A and 321B to form a magnetic coupling ring with moreturns.

According to some embodiments, the layouts in FIGS. 3A, 3B and 3C arereferred to herein as “edge coupling” because all magnetic couplingturns and transformer turns are planer turns disposed on the same planarsurface or layer of an integrated circuit device. As discussed above,the transformer/inductor 322 and the magnetic coupling turns 321A and321B can magnetically couple to one another to form one or moretransformers. According to some embodiments, the inductors/transformerscould be 4-port transformers/inductors, a 6-port trifilar, multi-port(8-port, 10-port, or N-port) transformers, or any layout of devices thatcan generate magnetic fields. In some embodiments, the space between thetransformer/inductors 322 and the magnetic coupling turns 321A and 321Bis filled with a non-magnetic material. In alternative embodiments,however, the magnetic coupling turns need not be in the same plane asthe turn(s) of the primary inductor or transformer.

FIG. 4A is a three-dimensional (3-D) layout diagram illustrating atransformer 400 having a transformer/inductor 402 and two magneticcoupling turns 401A and 401B disposed on the outside and above thetransformer/inductor 402, in accordance with some embodiments. Themagnetic coupling turns 401A and 401B form a magnetic coupling ring 401.According to some embodiments, the transformer/inductor 402 is atransformer which has two inductors L₁ and L₂ (not illustrated in FIG.4A) similar to the embodiments illustrated in FIGS. 1A 1B and 1C.According to some embodiments, the transformer/inductor 402 is atransformer which has more than two inductors. The magnetic couplingturns 401A and 401B are top coupling turns above thetransformer/inductor 402, which means that both the magnetic couplingturns 401A and 401B are raised above the transformer/inductor 402.According to some embodiments, the magnetic coupling turns 401A and 401Bhave larger sizes than the transformer/inductor 402. According to someembodiments, the magnetic coupling turns 401A and 401B have smallersizes than the transformer/inductor 402. According to some embodiments,the magnetic coupling turns 401A and 401B have the same sizes as thetransformer/inductor 402. According to some embodiments, one of themagnetic coupling turns 401A and 401B has a larger size than thetransformer/inductor 402. According to some embodiments, one of themagnetic coupling turns 401A and 401B has a smaller size than thetransformer/inductor 402. According to some embodiments, one of themagnetic coupling turns 401A and 401B has the same size as thetransformer/inductor 402. The magnetic coupling turns 401A and 401B areelectrically connected to allow electrical current to flow through bothof them. According to some embodiments, additional turns can be added tothe transformer/inductor 402. According to some embodiments, additionalturns can be added above the transformer/inductor 402, and electricallyconnected to the magnetic coupling turns 401A and 401B to form amagnetic coupling ring with more turns. As discussed above, thetransformer/inductors 402 and the magnetic coupling turns 401A, 401B canmagnetically couple to one another to form one or more transformers 400.In some embodiments, the space between the transformer/inductors 402 andthe magnetic coupling turns 401A and 401B is filled with non-magneticmaterial as space filler.

FIG. 4B is a layout diagram illustrating a transformer 410 having atransformer/inductor 412 and two magnetic coupling turns 411A and 411Bdisposed outside and below the turn(s) of the transformer/inductor 412,in accordance with some embodiments. The magnetic coupling turns 411Aand 411B form a magnetic coupling ring 411. According to someembodiments, the magnetic coupling turns 411A and 411B have larger sizesthan the transformer/inductor 412. According to some embodiments, themagnetic coupling turns 411A and 411B have smaller sizes than thetransformer/inductor 412. According to some embodiments, the magneticcoupling turns 411A and 411B have the same sizes as thetransformer/inductor 412. According to some embodiments, one of themagnetic coupling turns 411A and 411B has a larger size than thetransformer/inductor 412. According to some embodiments, one of themagnetic coupling turns 411A and 411B has a smaller size than thetransformer/inductor 412. According to some embodiments, one of themagnetic coupling turns 411A and 411B has the same size as thetransformer/inductor 412. The magnetic coupling turns 411A and 411B areelectrically connected to allow electrical current to flow through bothof them. According to some embodiments, additional turns can be added tothe transformer/inductor 412. According to some embodiments, additionalturns can be added above the transformer/inductor 412, and electricallyconnected to the magnetic coupling turns 411A and 411B to form amagnetic coupling ring with more turns. The transformer/inductors 412,the magnetic coupling turns 411A and 411B can magnetically couple to oneanother to form one or more transformers 410. In some embodiments, thespace between the transformer/inductor 412 and the magnetic couplingturns 411A, 411B is filled with non-magnetic material.

FIG. 4C is a layout diagram illustrating a transformer 420 having atransformer/inductor 422 and a top magnetic coupling turn 421A and abottom magnetic coupling turn 421B in accordance with some embodiments.The magnetic coupling turns 421A and 421B form a magnetic coupling ring421. The transformer/inductor 422 is either a transformer or aninductor, the magnetic coupling turn 421A is a coupling turn disposedoutside and above the transformer/inductor 422, which means that themagnetic coupling turns 421A is larger and raised above thetransformer/inductor 422. The magnetic coupling turn 421B is a couplingturn disposed outside and below the transformer/inductor 422, whichmeans that the magnetic coupling turn 421B is larger and located belowthe transformer/inductor 422. According to some embodiments, themagnetic coupling turns 421A and 421B have larger sizes than thetransformer/inductor 422. According to some embodiments, the magneticcoupling turns 421A and 421B have smaller sizes than thetransformer/inductor 422. According to some embodiments, the magneticcoupling turns 421A and 421B have the same sizes as thetransformer/inductor 422. According to some embodiments, one of themagnetic coupling turns 421A and 421B has a larger size than thetransformer/inductor 422. According to some embodiments, one of themagnetic coupling turns 421A and 421B has a smaller size than thetransformer/inductor 422. According to some embodiments, one of themagnetic coupling turns 421A and 421B has the same size as thetransformer/inductor 422. The magnetic coupling turn 421A and 421B areelectrically connected to allow electrical current to flow through bothof them. According to some embodiments, additional turns can be added tothe transformer/inductor 422. According to some embodiments, additionalturns can be added above the transformer/inductor 422, and electricallyconnected to the magnetic coupling turns 421A and 421B to form amagnetic coupling ring with more turns.

According to some embodiments, the layouts illustrated in FIGS. 4A, 4Band 4C are referred to herein as “broadside coupling” because allmagnetic coupling turns and inductor turns are not in the same planarsurface. The transformer/inductors 422, the magnetic coupling turns 421Aand 421B can magnetically couple to one another to form one or moretransformers 420. In some embodiments, the space between thetransformer/inductors 422 and the magnetic coupling turns 421A, 421B isfilled with non-magnetic material.

According to some embodiments, the inductor/transformer could be 4-porttransformers or inductors, 6-port trifilar, multi-port (8-port, 10-port,or N-port) transformers, or any layout of devices that could generate amagnetic field. According to some embodiments, each of theimplementations in FIGS. 3A, 3B, 3C, can be combined with each theimplementations in 4A, 4B and 4C. For example, outside magnetic turnscan be added all above or all below a primary inductor, or some of theturns above the primary inductor and some of the turns below the primaryinductor, or all on the same surface as the primary inductor. The sameis true for inside turns. More generally, according to some embodiments,additional turns can be added above, below, inside or outside theprimary inductor, additional turns can have the same size as the primaryinductor, additional turns can be on the same surface as the primaryinductor. Additional turns can be added as a combination of any theabove configurations. According to some embodiments, the number of turnsof the primary inductor is no smaller than 1. According to someembodiments, the number of turns of the magnetic coupling is no smallerthan 2.

FIGS. 5A and 5B provide graphs illustrating the magnetic couplingswitching-on effect on the quality factor of a single switch thatcontrols the magnetic coupling ring. The horizontal axis is frequency inthe unit of GHz, and the vertical axis is quality factor. Quality factorQ is defined as:

${Q = \frac{\omega\; L}{R}},$which means when inductance L decreases and resistance R increases, Qdecreases. The oscillation frequency f_(osc) is defined as:

${f_{osc} - \frac{1}{2\pi\sqrt{LC}}},$which means that with a decrease of L of approximately 33% (shown inFIG. 5B, between graphs 505 and 506), f_(osc) increases approximately25% thereby increasing the tuning range. The increase in tuning range isillustrated in FIG. 5A. The curve 501 illustrates the Quality-Frequencyrelationship when the magnetic coupling is switched off. When themagnetic coupling is switched off, the frequency tuning range of theinductors is from 10 GHz to 17 GHz. The darkened segment 503 of thecurve 501 designates the Quality-Frequency relationship in the frequencyrange of 10 GHz 17 GHz (shown as between the dashed vertical lines 520,521). The tuning range is 10 GHz˜17 GHz due to the impact of parasiticcurrent in the inductors when the switch is off. Therefore, the singleswitch must be turned ON to extend the tuning range beyond 17 GHz. Whenthe switch is switched on, the curve 501 changes to curve 502, and thetuning range is extended to 10 GHz˜20 GHz as shown between the verticallines 520 and 522. Thus, a tuning range of 10 GHz˜20 GHz is achievedwhen the magnetic coupling is introduced when the switch is on.

The magnetic coupling is switched on when the frequency approaches 17GHz. When the magnetic coupling is switched on, the Quality-Frequencyrelationship drops from the darkened segment 503 on curve 501 to thedarkened segment 504 on the curve 502. At 17 GHz, the correspondingquality factor on the darkened segment 504 drops below the lowestquality factor value of 3.8 on segment 503, which is designated byhorizontal dashed line 519. As the frequency changes from 17 GHz to 20GHz, the quality factor increases above 3.8, illustrated by the dashedline 519.

FIG. 5B illustrates the inductance change when the magnetic coupling isturned off (505), and when the magnetic coupling is turned on (506). Atthe frequency 20.0 GHz, the inductance drops about 33%.

Thus, the magnetic coupling provides more than 20% tuning frequencyrange enhancement. In the frequency range 10 GHz˜17 GHz (illustrated asdarkened segment 503 between the vertical lines 520 and 521), the lowestquality factor value is approximately 3.8. When the switch is switchedon in the curve 502, the quality factor decreases approximately 32% dueto magnetic coupling, but the tuning range is extended by approximately20%. In the extended tuning range designated as darkened segment 504 inFIG. 5A, the quality of at least part of tuning range 504 is below thelowest quality value of 503, which is 3.8 (shown as horizontal dashedline 519).

FIGS. 5C and 5D provide graphs illustrating the magnetic couplingswitching-on effect on the quality factor of two switches. The curve 510illustrates the Quality-Frequency relationship when the switches are alloff. The curve 511 illustrates the Quality-Frequency relationship whenone switch is switched on. The curve 512 illustrates theQuality-Frequency relationship when both switches are switched on. Afterusing the two switches in the magnetic coupling, the magnetic qualityfactors of all graphs are higher than the lowest quality value of 3.8shown as 519 in FIG. 5A without degrading the whole band performance. Ascompared to FIG. 5A, the frequency tuning range (10 GHz˜17 GHz) isextended when one switch (S0) is switched on in curve 511, as shown bydarkened segment 513 between vertical arrows 523 and 524. When thesecond switch (S1) is switched on, the tuning range is further extendedto approximately 20 GHz as shown by darkened segment 514 on curve 512.As shown in FIG. 5C, the quality factor in the extended range 513 (on511) and 514 (on 512) is higher than the lowest quality value of 3.8 inthe frequency range of 10 GHz˜17 GHz. (illustrated as horizontal dashedline 519). In some embodiments, overall, the quality factor is enhancedapproximately 16% without degrading the performance of the whole band.

FIG. 5D illustrates the inductance change when the magnetic coupling isswitched off (516), when one magnetic coupling is switched on (517), andwhen both magnetic coupling are switched on (518).

FIG. 6A is a layout diagram illustrating an adjustable multi-turnmagnetic coupling transformer with two switches in accordance with someembodiments. The transformer 600 include a first inductor 601, a secondinductor 602, a first magnetic coupling turn 603A, a second magneticcoupling turn 603B and a variable switch 604 with two transistors 604Aand 604B. The inductors 601 and 602 have similar three dimensionallayout as illustrated in FIG. 1A. According to some embodiments,adjustable MOS switches are implemented to change the inductance throughdigital control. The magnetic coupling turns 603A and 603B form themagnetic coupling ring 603. According to some embodiments, the qualityfactor of the whole band is enhanced. According to some embodiments, twoturns 603A and 603B are implemented outside the two inductors 601 and602 similar to the discussion in FIGS. 1A and 1B. Inductors 602 and 601are illustrated in different shades similar to previous figures. Twotransistors S0 604A and S1 604B are implemented as switches for thecorresponding magnetic coupling turns 603A and 603B. When thecorresponding transistor is switched ON, then the electrical currentflows inside the corresponding turn. As a result, magnetic field isgenerated by the corresponding turn. According to some embodiments, thetransistors are N-MOS transistors. According to some other embodiments,the transistors are P-MOS transistors. According to some embodiments,the transistors are a combination of P-MOS and N-MOS transistors.According to some embodiments, the transistors are controlled bycorresponding control logic units. The size of the MOS transistor ismeasured by W/L, where W is the width of the MOS transistor and L is thelength of the MOS transistor. According to some embodiments, the size ofthe S1 604B is 10 times that of the S0 604A. In some embodiments, theresistance of the MOS switches indicated by resistance symbol 604 isinversely proportional to the size of the MOS switches. The switch 604is effectively a variable resistor formed by the MOS switches 604A and604B.

FIG. 6B is a graph illustrating a comparison of the inductance andswitch resistance of an adjustable multi-turn magnetic couplingtransformer with two switches in accordance with some embodiments. Thehorizontal axis is resistance in the unit of ohms, and the vertical axisis inductance in the unit of pico Henries (pH). OFF designates thecorresponding resistance and inductance when the transistors 603A and603B are both switched off. S0 designates the corresponding resistanceand inductance when the transistor 603A (S0) is switched on. S1designates the corresponding resistance and inductance when both thetransistors 603A (S0) and 603B (S1) are switched on. According to someembodiments, the resistance is:

$R_{ON} = {\frac{1}{\frac{1}{2}\mu_{n}C_{OX}\frac{W}{L}\left( {V_{GS} - V_{TH}} \right)^{2\;}}.}$

FIG. 7 is a layout diagram illustrating an adjustable multi-turnmagnetic coupling transformer 700 having a plurality of NMOS switches704A-704N, in accordance with some embodiments. The transformer 700include a first inductor 701, a second inductor 702, a first magneticcoupling turn 703A, a second magnetic coupling turn 703B and a variableswitch 704 with N transistors 704A-704N. The inductors 701 and 702 havesimilar three dimensional layout as illustrated in FIG. 1A. The magneticcoupling turns 703A and 703B form the magnetic coupling ring 703.Similar to the discussion of FIGS. 6A and 6B, the magnetic couplingturns 703A and 703B are controlled by the variable switch 704 (shown asa variable resistor) implemented by N NMOS transistors connected asparallel switches. According to some embodiments, the sizes of the NMOSswitches can be varied as desired. According to some embodiments, therelative sizes of the all the NMOS switches follow a binary sequence: 1,2, 4, 8, 16, etc. from S0 to SN. According to some embodiments, therelative sizes of the all the NMOS switches follow a decimal sequence:1, 10, 100, 1000, 10000, etc. from S0 to SN. In some embodiments, theresistance of the MOS switches indicated by variable resistor symbol 704is inversely proportional to the size of the MOS switches. According tosome embodiments, the variable switch 704 includes N PMOS transistors704A, 704B, . . . 704N, and all discussions regarding variable switchwith NMOS transistors above also apply to variable switch with PMOStransistors.

According to some embodiments, the N switches are of the same type.According to some embodiments, the N switches are of the differenttypes. According to some embodiments, the N switches are a combinationof NMOS, PMOS and bipolar junction transistors. In alternativeembodiments, the N switches can be any type of switch device that can beturned on and off with a desired amount of resistance when turned on.

FIG. 8A is a schematic diagram illustrating a circuit implementation ofan adjustable multi-turn magnetic coupling transformer 800, inaccordance with some embodiments. A first transistor 801 and a secondtransistor 802 are connected in parallel, and they are further connectedto inductors 815 and 816 to form a loop. When either one of transistors801 and 802, or both of them, is/are switched on, electrical currentflows in the loop formed by the inductor 815, inductor 816, andtransistors 801 and 802. The magnetic field generated by such electricalcurrent is either in the same direction, or in the opposite direction ofthe transformer(s) in other parts of the circuits discussed below.Inductors 809 and 810 are connected in serial. Capacitors 803 and 805are separated by a switch 804. Capacitors 806 and 808 are separated by aswitch 807. In a similar configuration, inductors 811 and 812 areconnected in serial. Capacitors 817 and 819 are separated by a switch818. Capacitors 820 and 822 are separated by a switch 821. A resistor827 is connected to a predetermined voltage supply (VB) at one end andto a node between inductors 811 and 812 at a second end. A capacitor 828has one plate connected to ground and a second plate connected to thenode between inductors 811 and 812.

According to some embodiments, the transistors 801 and 802 form avariable switch. The loop formed by the inductors 815 and 816 is themagnetic coupling ring, and the magnetic coupling ring is controlled bythe variable switch including two transistors 801 and 802. According tosome embodiments, there are a plurality of magnetic coupling turns inthe magnetic coupling ring. According to some embodiments, the variableswitch includes more than two transistors. According to someembodiments, the variable switch includes other switching devices.According to some embodiments, the inductors 809 and 810 form the L₁inductor (for example, 101) and the inductors 811 and 812 form the L₂inductor (for example 102), as illustrated in FIGS. 1B and 1C.

The gate of the transistor 813 is connected to the inductor 811.Similarly, the gate of the transistor 814 is connected to the inductor812. The source of the transistor 813 is connected to the source of thetransistor 814. The drain of the transistor 813 is connected to thesource of 823. Similarly, the drain of 814 is connected to the source of826. The gates of 823, 824, 825 and 826 are connected in a mannerillustrated in the figure. The drains of 823, 824, 825 and 826 areappropriately grounded. The operation of the circuit of FIG. 8A isdiscussed in further detail below in connection with the correspondinglayout diagram in FIG. 8B.

FIG. 8B is a schematic plot illustrating the signal waveforms on VD+/−,VG+/−, BUF+/− and FOUT respectively in accordance with some embodiments.Signal waveform 891 is the waveform on VD+ and VD− with a peak-to-peakvalue of 500 mV and an average of VDD. Signal waveform 892 is thewaveform on VG+ and VG− with a peak-to-peak value of 1000 mV and anaverage of VDD. Signal waveform 893 is the waveform on BUF+ and BUF−with a peak-to-peak value of 400 mV and an average of VDD/2. Signalwaveform 894 is the waveform on FOUT with a peak-to-peak value of 800 mVand an average of VDD/2.

FIG. 9 is a layout diagram illustrating a point-symmetricpseudo-differential layout corresponding to the circuit implementationof an adjustable multi-turn magnetic coupling transformer in FIG. 8A, inaccordance with some embodiments. The layout includes a firsttransformer 910, a second transformer 920, a first switched capacitorbank 904A and a second switched capacitor bank 904B. The firsttransformer 910 includes a first inductor 902A, a second inductor 903Aand a first magnetic coupling ring 901A. The inductors 902A and 903Ahave similar three dimensional layout as illustrated in FIG. 1A. Thesecond transformer 920 includes a third inductor 902B, a fourth inductor903B and a second magnetic coupling ring 901B. The inductors 902B and903B have similar three dimensional layout as illustrated in FIG. 1A

The loop formed by the switches 801, 802 and inductors 815, 816corresponds to the outside magnetic coupling rings 901A and 901B, whichcorrespond to and have similar functionality as the magnetic couplingturn 101 of FIGS. 1B and 1C, and magnetic coupling turns 201A, 201B and201C of FIGS. 2A, 2B and 2C, for example, discussed above. FIGS. 3A, 3B,3C, 4A, 4B and 4C show additional embodiments of the magnetic couplingturns that may be implemented by turns 901A and 901B of FIG. 9. Theinductors 809, 810 correspond to the inductors 902A and 902B, and theinductors 811, 812 correspond to the inductors 903A and 903B. Accordingto some embodiments, the inductors 902A/902B and 903A/903B couple toform a transformer, which is also discussed in FIG. 1A through FIG. 4C.All discussions above regarding magnetic coupling turns and transformersapply here for 901A/901B, 902A/902B and 903A/903B, and theircorresponding schematics in FIG. 8A. The capacitors 803, 805, 806, 808,817, 819, 820 and 822 correspond to the capacitors in the switchedcapacitor banks 904A and 904B.

According to some embodiments, variable switches 801 and 802 of FIG. 8Acontrol the magnetic coupling ring 901A and 901B of FIG. 9.Additionally, the switches 804 and 807 are connected in parallel toprovide a variable-impedance switch for the inductors 809 and 810.Similarly, the switches 818 and 821 are also connected in parallel toprovide a variable-impedance switch for the inductors 811 and 812.

According to some embodiments, the transformers/inductors and magneticcoupling turns 901A, 902A and 903A are point symmetric to thetransformers/inductors and magnetic coupling turns 901B, 902B and 903Brelative to the geometric center point 990. As used herein, if a figureor graph can be rotated 180° about a center point P and resulting figureor graph is identical to the original, then the figure or graph is saidto be “point symmetric” relative to the point of symmetry P. Themagnetic coupling turn 901A being point-symmetric to the magneticcoupling turn 901B relative to the point 990 means that when themagnetic coupling turn 901A is rotated 180 degrees with 990 as therotation center, the magnetic coupling turn 901A overlaps with themagnetic coupling turn 901B. The same applies to the inductors 902A/B,903A/B and capacitor bank 904A/B. The switched capacitor bank 904A isalso arranged in a way that is point-symmetric to the switched capacitorbank 904B. According to some embodiments, the directions of the electriccurrents inside the magnetic coupling turns 901A, and inductors 902A,903A are opposite to the directions of the electric currents inside themagnetic coupling turns 901B, and inductors 902B 903B, so that theoverall magnetic field inside the magnetic coupling turns and inductors901A, 902A and 903A has an opposite direction as compared to the overallmagnetic field inside the magnetic coupling turns and inductors 901B,902B and 903B.

According to some embodiments, the ground 905 and the power 906 areseparated by a plurality of capacitors. The power 906 and the ground 905provide power to the magnetic coupling turns 901A/B,transformers/inductors 902A/B, 903A/B, and capacitor bank 904A/B.According to some embodiments, the power 906 is arranged as a squarewith sides of length 125 μm. The ground is arranged as another squareinside the square of power 906 and separated by capacitors 907. Theoverall scheme is point symmetric. As indicated earlier, all discussionsin FIGS. 1A through 7B apply to the schematic FIG. 8A and layout FIG.8B.

According to some embodiments, an integrated circuit device isdisclosed. The integrated circuit device include at least one inductorhaving at least one turn, a magnetic coupling ring positioned adjacentto the at least one inductor, the magnetic coupling ring comprising atleast two magnetic coupling turns, the at least two magnetic couplingturns are disposed adjacent to the at least one turn to enable magneticcoupling between the at least two magnetic coupling turns and the atleast one turn The integrated circuit device also includes a powerelectrode and a ground electrode, wherein the power electrode and theground electrode are coupled to the at least one inductor and themagnetic coupling ring to provide a first current in the at least oneinductor having a direction opposite to a second current in the magneticcoupling ring. According to some embodiments, all of the at least twomagnetic coupling turns are outside the at least one turns of theinductor. According to some embodiments, all of the at least twomagnetic coupling turns are inside the at least one turns of theinductor. According to some embodiments, at least one of the at leasttwo magnetic coupling turns are outside the at least one turns of theinductor, and at least one of the at least two magnetic coupling turnsare inside the at least one turns of the inductor. According to someembodiments, all of the at least two magnetic coupling turns are abovethe at least one turns of the inductor. According to some embodiments,all of the at least two magnetic coupling turns are below the at leastone turns of the inductor. According to some embodiments, at least oneof the at least two magnetic coupling turns are above the at least oneturns of the inductor, and at least one of the at least two magneticcoupling turns are below the at least one turns of the inductor.

According to some embodiments, another integrated circuit device isdisclosed. The device includes at least one inductor having at least oneturn, a magnetic coupling ring positioned adjacent to the at least oneinductor, the magnetic coupling ring comprising at least one magneticcoupling turn, wherein the at least one magnetic coupling turn isdisposed adjacent to the at least one turn to enable magnetic couplingbetween the at least one magnetic coupling turn and the at least oneturn. The integrated circuit device also includes a plurality ofswitches coupling the at least one magnetic coupling turn for switchingon and off the at least one magnetic coupling turns, and a powerelectrode and a ground electrode, the power electrode and the groundelectrode are coupled to the at least one inductor and the magneticcoupling turn to provide a first current in the at least one inductorhaving a direction opposite to a second current in the magnetic couplingturn. According to some embodiments, the plurality of switches are MOStransistors. According to some embodiments, the plurality of switchesare PMOS transistors. According to some embodiments, the plurality ofswitches are NMOS transistors. According to some embodiments, theplurality of switches are bipolar junction transistors. According tosome embodiments, the plurality of switches are a combination of PMOS,NMOS and bipolar junction transistors. According to some embodiments,the size ratio of the N-th MOS of the plurality of MOS transistors tothe first MOS transistor is 2{circumflex over ( )}(N−1). According tosome embodiments, the size ratio of the N-th MOS of the plurality of MOStransistors to the first MOS transistor is 10{circumflex over ( )}(N−1).

According to some embodiments, another integrated circuit device isdisclosed. The integrated circuit device includes a first transformercomprising a first inductor, a second inductor and a first magneticcoupling ring and a second transformer comprising a third inductor, afourth inductor and a second magnetic coupling ring. The first inductoris point-symmetric with respect to the third inductor relative to acenter point of the integrated circuit device. The second inductor ispoint-symmetric to the fourth inductor with respect to the center point.The first magnetic coupling ring is point-symmetric with respect to thesecond magnetic coupling turn relative to the center point. Theintegrated circuit device also includes a power electrode and a groundelectrode, the power electrode and the ground electrode are coupled tothe first and the second inductor and the first magnetic coupling turnto provide a first current in the first and the second inductor having adirection opposite to a second current in the first magnetic couplingturn, the power electrode and the ground electrode are coupled to thethird and the fourth inductors and the second magnetic coupling ring toprovide a third current in the third and fourth inductors having adirection opposite to a fourth current in the second magnetic couplingring.

According to some embodiments, the first inductor and the third inductorof the integrated circuit device are separated by a first plurality ofcapacitors, and the first plurality of capacitors are arranged in twogroups which are point-symmetric to each other. According to someembodiments, the second inductor and the fourth inductor of theintegrated circuit device are separated by a second plurality ofcapacitors, and the second plurality of capacitors are arranged in twogroups which are point-symmetric to each other. According to someembodiments, the first magnetic coupling turn and the second magneticcoupling turn of the integrated circuit device are separated by a thirdplurality of capacitors, and the third plurality of capacitors arearranged in two groups which are point-symmetric to each other.According to some embodiments, the power electrode and the groundelectrode of the integrated circuit device are separated by a fourthplurality of capacitors, the power electrode is arranged as a squarewith sides of 125 μm, the power electrode is coupled to the first andthe third inductors, and the ground is coupled to the second and thefourth inductors.

The foregoing outlines features of several embodiments so that thoseordinary skilled in the art may better understand the aspects of thepresent disclosure. Those skilled in the art should appreciate that theymay readily use the present disclosure as a basis for designing ormodifying other processes and structures for carrying out the samepurposes and/or achieving the same advantages of the embodimentsintroduced herein. Those skilled in the art should also realize thatsuch equivalent constructions do not depart from the spirit and scope ofthe present disclosure, and that they may make various changes,substitutions, and alterations herein without departing from the spiritand scope of the present disclosure.

What is claimed is:
 1. An integrated circuit device, comprising: atransformer comprising a first inductor and a second inductor, whereinthe first and second inductors each comprises at least one turn; and amagnetic coupling ring comprising at least two magnetic coupling turns,wherein the at least two magnetic coupling turns are each disposed to beeither surrounding or surrounded by the transformer in a top view toenable magnetic coupling between the magnetic coupling ring and thetransformer, wherein the at least two magnetic coupling turns are in atleast two different levels with respect to one another, and wherein thetransformer is configured to conduct a first current in a firstdirection and the magnetic coupling ring is configured to conduct asecond current in a second direction opposite the first direction. 2.The integrated circuit device of claim 1, wherein all of the at leasttwo magnetic coupling turns are disposed surrounding the transformer. 3.The integrated circuit device of claim 1, wherein all of the at leasttwo magnetic coupling turns are disposed surrounded by the transformer.4. The integrated circuit device of claim 1, wherein at least one of theat least two magnetic coupling turns is disposed surrounding thetransformer, and at least one of the at least two magnetic couplingturns is disposed surrounded by the transformer.
 5. The integratedcircuit device of claim 1, wherein all of the at least two magneticcoupling turns are above the level of the transformer.
 6. The integratedcircuit device of claim 1, wherein all of the at least two magneticcoupling turns are below the level of the transformer.
 7. The integratedcircuit device of claim 1; wherein at least one of the at least twomagnetic coupling turns is above the level the transformer, and at leastone of the at least two magnetic coupling turns is below the level ofthe transformer.
 8. An integrated circuit device, comprising: atransformer comprising a first inductor and a second inductor, whereinthe first and second inductors each comprises at least one turn; amagnetic coupling ring comprising a plurality of magnetic couplingturns, wherein the plurality of magnetic coupling turns are eachdisposed adjacent to the transformer in a top view to enable magneticcoupling between the magnetic coupling ring and the transformer, whereinthe plurality of magnetic coupling turns are in at least two differentlevels with respect to one another, and wherein the transformer isconfigured to conduct a first current in a first direction and themagnetic coupling ring is configured to conduct a second current in asecond direction opposite the first direction; and a plurality ofswitches coupled to the plurality of magnetic coupling turns forswitching on and off the plurality of magnetic coupling turns.
 9. Theintegrated circuit device of claim 8, wherein the plurality of switchesare metal-oxide-semiconductor (MOS) transistors.
 10. The integratedcircuit device of claim 8, wherein the plurality of switches are p-typeMOS (PMOS) transistors.
 11. The integrated circuit device of claim 8,wherein the plurality of switches are n-type MOS (NMOS) transistors. 12.The integrated circuit device of claim 8, wherein the plurality ofswitches are bipolar junction transistors.
 13. The integrated circuitdevice of claim 8, wherein the plurality of switches are a combinationof PMOS, NMOS and bipolar junction transistors.
 14. The integratedcircuit device of claim 9, wherein the size ratio of the N-th MOS of theplurality of MOS transistors to the first MOS transistor is 2{circumflexover ( )}(N−1).
 15. The integrated circuit device of claim 9, whereinthe size ratio of the N-th MOS of the plurality of MOS transistors tothe first MOS transistor is 10{circumflex over ( )}(N−1).
 16. Anintegrated circuit device, comprising: a first transformer comprising afirst inductor, a second inductor and a first magnetic coupling ring,wherein the first transformer is configured to conduct a first currentin a first direction and the first magnetic coupling ring is configuredto conduct a second current in a second direction opposite the firstdirection; and a second transformer comprising a third inductor, afourth inductor and a second magnetic coupling ring, wherein the secondtransformer is configured to conduct a third current in a thirddirection and the second magnetic coupling ring is configured to conducta fourth current in a fourth direction opposite the third direction, andwherein the first inductor is point-symmetric with respect to the thirdinductor relative to a center point of the integrated circuit device,the second inductor is point-symmetric with respect to the fourthinductor relative to the center point, and the first magnetic couplingring is point-symmetric with respect to the second magnetic couplingring relative to the center point.
 17. The integrated circuit device ofclaim 16, wherein the first inductor and the second inductor areseparated by a first plurality of capacitors, and the first plurality ofcapacitors are arranged in two groups which are point-symmetric to eachother.
 18. The integrated circuit device of claim 16, wherein the thirdinductor and the fourth inductor are separated by a second plurality ofcapacitors, and the second plurality of capacitors are arranged in twogroups which are point-symmetric to each other.
 19. The integratedcircuit device of claim 16, wherein the first magnetic coupling ring andthe second magnetic coupling ring are separated by a third plurality ofcapacitors, and the third plurality of capacitors are arranged in twogroups which are point-symmetric to each other.
 20. The integratedcircuit device of claim 16, wherein each of the first magnetic couplingring and the second magnetic coupling ring comprises at least twomagnetic coupling turns, wherein each of the at least two magneticcoupling turns is disposed to be either surrounding or surrounded by thefirst transformer and the second transformer, respectively, in a topview.